People exercised to the NHK morning radio calisthenics broadcast at a Tokyo park on Thursday. Within four decades, almost half the people in the world's third-largest economy will be 65 years or older, compared with one in four now.

People exercised to the NHK morning radio calisthenics broadcast at a Tokyo park on Thursday. Within four decades, almost half the people in the world's third-largest economy will be 65 years or older, compared with one in four now.